On arriving in Uthodurn, the get together Found Umagorn Smeltborne, a blacksmith. Umagorn understood the sword they were aiming to have repaired was Dwueth'var, the Star Razor. He tells them that he can take care of it, but he will need iceflex, shaped by a white dragon breathing on mythril. https://goliathbarbarian25791.bloguetechno.com/a-secret-weapon-for-dnd-serpentblood-63613445